L'art de fabriquer le salin et la potasse ; suivi des Expériences sur les moyens de multiplier la fabrication de la potasse ([Reprod.]) / par le citoyen Pertuis, & par le citoyen B. G. Sage... (Bavarian library copy) and the Lavoisier article from 1779 with the same title (catalog entry). Earlier I confused the Lavoisier book with this article on just Salpeter production, which Lavoisier also wrote when a regisseur at the poudre commission.
At first I thought that Pertuis and Sage were regisseurs with Lavoisier, but that seems unlikely based on this essay. At the same time, the name and the structure look so similar, that one suspects it might be a reprint, cleansed for the Republic (as the labels citoyen make one suspect).
One thing is certain: Lavoisier was executed in 1794.
Prof Marco Beretta of the University of Bologna, in a private communication, pointed out [typos rectified, RCK], that L'art de fabriquer le salin et la potasse was
... originally published anonymously upon a report made by Tillet, Cadet, Sage and Lavoisier. The report was probably written and conducted by Lavoisier. In the second ed. the experiments by Pertuis were added and for [from?] the index it seems that a few experiments by Sage were also added to the original ones. Thus, although Sage and Pertuis claim to be the author of the whole work[, this] was misleading to say the least, [but] their additions, apparently not particularly significant, justified the appearance of their names on the frontispiece.However, an analytical comparison of the two editions remains a desideratum.